I've been sort of obsessed with the spouse as best friend mantra of late.

We had one of those "out of the mouths of babes" moments in our house -- she asked me who my best friend was, and when I said, "Daddy," she rolled her eyes and told me, "No, he's just your husband."

In my playbook, they're the same thing.

You can marry for the great sex, but what happens when you're in the middle of your period or he's just had his vasectomy operation ... you have to have SOMETHING to talk about until you can have sex again. And it doesn't hurt to have sex with a guy who will giggle along with you when you do one of these.

A f--k buddy won't.

A best friend will.

At the risk of sounding like an old-fashioned fuddy duddy, when I put it out to my friends on Facebook, everyone agreed. If you're not one another's best friends, why are you even married?

As my friend Beret said: "We share everything in our lives, we work as a team, and we know everything about each other. I love being married!"

Of course this argument quickly gets entangled in the "can married people have opposite sex" friends? I'm no Harry Burns -- I think you absolutely can. And most Americans would agree -- one Match.com poll found 83 percent of the 1,500 surveyed say these friendships can and do exist.

But there are friendships ... and then there are marriages.

In a Woman's Day poll, a full third of respondents said being "best friends" was the reason their marriage was surviving. Sounds low until you consider this: another 27 percent said their marriage wasn't successful at all.